The research program is intended to provide information on the mechanism of action of the visual receptor complex in the initiation, adaptation, and maintenance of vision. An understanding of how light is translated to an electrical signal in vision may also be relevant to an understanding of the mechanism of operation of other sensory or receptor processes, such as taste, hearing, pain etc., and hormone or synaptic events. In order to obtain the required information, a variety of techniques and systems have been used. These include biochemical and physical studies of the conformation changes of the visual pigment rhodopsin in extracted detergent solution, in an artificial membrane system, and in excised retinas. In addition, direct studies on the relation between rhodopsin conformation changes and receptor potentials have been performed by simultaneous spectral and electrical measurements in excised retinas, and by observing the effect of selected chemicals on the late receptor potential. Finally, biochemical and photochemical studies have been undertaken to observe changes associated with visually deficient mutants of Drosophila melanogaster.